Custom orchestration status in Durable Functions (Azure Functions)

Article
2022-09-23

Custom orchestration status lets you set a custom status value for your orchestrator function. This status is provided via the HTTP GetStatus API or the equivalent SDK API on the orchestration client object.

Sample use cases

Visualize progress

Clients can poll the status end point and display a progress UI that visualizes the current execution stage. The following sample demonstrates progress sharing:

Note

These C# examples are written for Durable Functions 2.x and are not compatible with Durable Functions 1.x. For more information about the differences between versions, see the Durable Functions versions article.

[FunctionName("E1_HelloSequence")]
public static async Task<List<string>> Run(
    [OrchestrationTrigger] IDurableOrchestrationContext context)
{
    var outputs = new List<string>();

    outputs.Add(await context.CallActivityAsync<string>("E1_SayHello", "Tokyo"));
    context.SetCustomStatus("Tokyo");
    outputs.Add(await context.CallActivityAsync<string>("E1_SayHello", "Seattle"));
    context.SetCustomStatus("Seattle");
    outputs.Add(await context.CallActivityAsync<string>("E1_SayHello", "London"));
    context.SetCustomStatus("London");

    // returns ["Hello Tokyo!", "Hello Seattle!", "Hello London!"]
    return outputs;
}

[FunctionName("E1_SayHello")]
public static string SayHello([ActivityTrigger] string name)
{
    return $"Hello {name}!";
}

E1_HelloSequence orchestrator function:

const df = require("durable-functions");

module.exports = df.orchestrator(function*(context){
    const outputs = [];

    outputs.push(yield context.df.callActivity("E1_SayHello", "Tokyo"));
    context.df.setCustomStatus("Tokyo");
    outputs.push(yield context.df.callActivity("E1_SayHello", "Seattle"));
    context.df.setCustomStatus("Seattle");
    outputs.push(yield context.df.callActivity("E1_SayHello", "London"));
    context.df.setCustomStatus("London");

    // returns ["Hello Tokyo!", "Hello Seattle!", "Hello London!"]
    return outputs;
});

E1_SayHello activity function:

module.exports = async function(context, name) {
    return `Hello ${name}!`;
};

`E1_HelloSequence` Orchestrator function

import azure.functions as func
import azure.durable_functions as df


def orchestrator_function(context: df.DurableOrchestrationContext):
    
    output1 = yield context.call_activity('E1_SayHello', 'Tokyo')
    context.set_custom_status('Tokyo')
    output2 = yield context.call_activity('E1_SayHello', 'Seattle')
    context.set_custom_status('Seattle')
    output3 = yield context.call_activity('E1_SayHello', 'London')
    context.set_custom_status('London')
    
    return [output1, output2, output3]

main = df.Orchestrator.create(orchestrator_function)

`E1_SayHello` Activity function

def main(name: str) -> str:
    return f"Hello {name}!"

`E1_HelloSequence` Orchestrator function

param($Context)

$output = @()

$output += Invoke-DurableActivity -FunctionName 'E1_SayHello' -Input 'Tokyo'
Set-DurableCustomStatus -CustomStatus 'Tokyo'

$output += Invoke-DurableActivity -FunctionName 'E1_SayHello' -Input 'Seattle'
Set-DurableCustomStatus -CustomStatus 'Seattle'

$output += Invoke-DurableActivity -FunctionName 'E1_SayHello' -Input 'London'
Set-DurableCustomStatus -CustomStatus 'London'


return $output

`E1_SayHello` Activity function

param($name)

"Hello $name"

@FunctionName("HelloCities")
public String helloCitiesOrchestrator(
        @DurableOrchestrationTrigger(name = "runtimeState") String runtimeState) {
    return OrchestrationRunner.loadAndRun(runtimeState, ctx -> {
        String result = "";
        result += ctx.callActivity("SayHello", "Tokyo", String.class).await() + ", ";
        ctx.setCustomStatus("Tokyo");
        result += ctx.callActivity("SayHello", "London", String.class).await() + ", ";
        ctx.setCustomStatus("London");
        result += ctx.callActivity("SayHello", "Seattle", String.class).await();
        ctx.setCustomStatus("Seattle");
        return result;
    });
}

@FunctionName("SayHello")
public String sayHello(@DurableActivityTrigger(name = "name") String name) {
    return String.format("Hello %s!", name);
}

And then the client will receive the output of the orchestration only when CustomStatus field is set to "London":

[FunctionName("HttpStart")]
public static async Task<HttpResponseMessage> Run(
    [HttpTrigger(AuthorizationLevel.Function, methods: "post", Route = "orchestrators/{functionName}")] HttpRequestMessage req,
    [DurableClient] IDurableOrchestrationClient starter,
    string functionName,
    ILogger log)
{
    // Function input comes from the request content.
    dynamic eventData = await req.Content.ReadAsAsync<object>();
    string instanceId = await starter.StartNewAsync(functionName, (string)eventData);

    log.LogInformation($"Started orchestration with ID = '{instanceId}'.");

    DurableOrchestrationStatus durableOrchestrationStatus = await starter.GetStatusAsync(instanceId);
    while (durableOrchestrationStatus.CustomStatus.ToString() != "London")
    {
        await Task.Delay(200);
        durableOrchestrationStatus = await starter.GetStatusAsync(instanceId);
    }

    HttpResponseMessage httpResponseMessage = new HttpResponseMessage(HttpStatusCode.OK)
    {
        Content = new StringContent(JsonConvert.SerializeObject(durableOrchestrationStatus))
    };

    return httpResponseMessage;
  }
}

const df = require("durable-functions");

module.exports = async function(context, req) {
    const client = df.getClient(context);

    // Function input comes from the request content.
    const eventData = req.body;
    const instanceId = await client.startNew(req.params.functionName, undefined, eventData);

    context.log(`Started orchestration with ID = '${instanceId}'.`);

    let durableOrchestrationStatus = await client.getStatus(instanceId);
    while (durableOrchestrationStatus.customStatus.toString() !== "London") {
        await new Promise((resolve) => setTimeout(resolve, 200));
        durableOrchestrationStatus = await client.getStatus(instanceId);
    }

    const httpResponseMessage = {
        status: 200,
        body: JSON.stringify(durableOrchestrationStatus),
    };

    return httpResponseMessage;
};

Note

In JavaScript, the customStatus field will be set when the next yield or return action is scheduled.

import json
import logging
import azure.functions as func
import azure.durable_functions as df
from time import sleep

async def main(req: func.HttpRequest, starter: str) -> func.HttpResponse:
    client = df.DurableOrchestrationClient(starter)    
    instance_id = await client.start_new(req.params.functionName, None, None)

    logging.info(f"Started orchestration with ID = '{instance_id}'.")

    durable_orchestration_status = await client.get_status(instance_id)
    while durable_orchestration_status.custom_status != 'London':
        sleep(0.2)
        durable_orchestration_status = await client.get_status(instance_id)

    return func.HttpResponse(body='Success', status_code=200, mimetype='application/json')

Note

In Python, the custom_status field will be set when the next yield or return action is scheduled.

@FunctionName("StartHelloCities")
public HttpResponseMessage startHelloCities(
        @HttpTrigger(name = "req") HttpRequestMessage<Void> req,
        @DurableClientInput(name = "durableContext") DurableClientContext durableContext,
        final ExecutionContext context) throws InterruptedException {

    DurableTaskClient client = durableContext.getClient();
    String instanceId = client.scheduleNewOrchestrationInstance("HelloCities");
    context.getLogger().info("Created new Java orchestration with instance ID = " + instanceId);

    OrchestrationMetadata metadata = client.waitForInstanceStart(instanceId, Duration.ofMinutes(5), true);
    while (metadata.readCustomStatusAs(String.class) != "London") {
        Thread.sleep(200);
        metadata = client.getInstanceMetadata(instanceId, true);
    }

    return req.createResponseBuilder(HttpStatus.OK).build();
}

Output customization

Another interesting scenario is segmenting users by returning customized output based on unique characteristics or interactions. With the help of custom orchestration status, the client-side code will stay generic. All main modifications will happen on the server side as shown in the following sample:

[FunctionName("CityRecommender")]
public static void Run(
  [OrchestrationTrigger] IDurableOrchestrationContext context)
{
  int userChoice = context.GetInput<int>();

  switch (userChoice)
  {
    case 1:
    context.SetCustomStatus(new
    {
      recommendedCities = new[] {"Tokyo", "Seattle"},
      recommendedSeasons = new[] {"Spring", "Summer"}
     });
      break;
    case 2:
      context.SetCustomStatus(new
      {
        recommendedCities = new[] {"Seattle, London"},
        recommendedSeasons = new[] {"Summer"}
      });
        break;
      case 3:
      context.SetCustomStatus(new
      {
        recommendedCities = new[] {"Tokyo, London"},
        recommendedSeasons = new[] {"Spring", "Summer"}
      });
        break;
  }

  // Wait for user selection and refine the recommendation
}

`CityRecommender` orchestrator

const df = require("durable-functions");

module.exports = df.orchestrator(function*(context) {
    const userChoice = context.df.getInput();

    switch (userChoice) {
        case 1:
            context.df.setCustomStatus({
                recommendedCities: [ "Tokyo", "Seattle" ],
                recommendedSeasons: [ "Spring", "Summer" ],
            });
            break;
        case 2:
            context.df.setCustomStatus({
                recommendedCities: [ "Seattle", "London" ],
                recommendedSeasons: [ "Summer" ],
            });
            break;
        case 3:
            context.df.setCustomStatus({
                recommendedCity: [ "Tokyo", "London" ],
                recommendedSeasons: [ "Spring", "Summer" ],
            });
            break;
    }

    // Wait for user selection and refine the recommendation
});

`CityRecommender` orchestrator

import azure.functions as func
import azure.durable_functions as df

def orchestrator_function(context: df.DurableOrchestrationContext):
    userChoice = int(context.get_input())

    if userChoice == 1:
        context.set_custom_status({
            'recommendedCities' : ['Tokyo', 'Seattle'], 
            'recommendedSeasons' : ['Spring', 'Summer']
        }))
    if userChoice == 2:
        context.set_custom_status({
            'recommendedCities' : ['Seattle', 'London']
            'recommendedSeasons' : ['Summer']
        }))
    if userChoice == 3:
        context.set_custom_status({
            'recommendedCities' : ['Tokyo', 'London'], 
            'recommendedSeasons' : ['Spring', 'Summer']
        }))



    # Wait for user selection and refine the recommendation

main = df.Orchestrator.create(orchestrator_function)

`CityRecommender` orchestrator

param($Context)

$userChoice = $Context.Input -as [int]

if ($userChoice -eq 1) {
    Set-DurableCustomStatus -CustomStatus @{ recommendedCities = @('Tokyo', 'Seattle'); 
                                             recommendedSeasons = @('Spring', 'Summer') 
                                            }  
}

if ($userChoice -eq 2) {
    Set-DurableCustomStatus -CustomStatus @{ recommendedCities = @('Seattle', 'London'); 
                                             recommendedSeasons = @('Summer') 
                                            }  
}

if ($userChoice -eq 3) {
    Set-DurableCustomStatus -CustomStatus @{ recommendedCities = @('Tokyo', 'London'); 
                                             recommendedSeasons = @('Spring', 'Summer') 
                                            }  
}

# Wait for user selection and refine the recommendation

@FunctionName("CityRecommender")
public String cityRecommender(
    @DurableOrchestrationTrigger(name = "runtimeState") String runtimeState) {
        return OrchestrationRunner.loadAndRun(runtimeState, ctx -> {
            int userChoice = ctx.getInput(int.class);
            switch (userChoice) {
                case 1:
                    ctx.setCustomStatus(new Recommendation(
                            new String[]{ "Tokyo", "Seattle" },
                            new String[]{ "Spring", "Summer" }));
                    break;
                case 2:
                    ctx.setCustomStatus(new Recommendation(
                            new String[]{ "Seattle", "London" },
                            new String[]{ "Summer" }));
                    break;
                case 3:
                    ctx.setCustomStatus(new Recommendation(
                            new String[]{ "Tokyo", "London" },
                            new String[]{ "Spring", "Summer" }));
                    break;
            }

            // Wait for user selection with an external event handler
        });
}

class Recommendation {
    public Recommendation() { }

    public Recommendation(String[] cities, String[] seasons) {
        this.recommendedCities = cities;
        this.recommendedSeasons = seasons;
    }

    public String[] recommendedCities;
    public String[] recommendedSeasons;
}

Instruction specification

The orchestrator can provide unique instructions to the clients via the custom state. The custom status instructions will be mapped to the steps in the orchestration code:

[FunctionName("ReserveTicket")]
public static async Task<bool> Run(
  [OrchestrationTrigger] IDurableOrchestrationContext context)
{
  string userId = context.GetInput<string>();

  int discount = await context.CallActivityAsync<int>("CalculateDiscount", userId);

  context.SetCustomStatus(new
  {
    discount = discount,
    discountTimeout = 60,
    bookingUrl = "https://www.myawesomebookingweb.com",
  });

  bool isBookingConfirmed = await context.WaitForExternalEvent<bool>("BookingConfirmed");

  context.SetCustomStatus(isBookingConfirmed
    ? new {message = "Thank you for confirming your booking."}
    : new {message = "The booking was not confirmed on time. Please try again."});

  return isBookingConfirmed;
}

const df = require("durable-functions");

module.exports = df.orchestrator(function*(context) {
    const userId = context.df.getInput();

    const discount = yield context.df.callActivity("CalculateDiscount", userId);

    context.df.setCustomStatus({
        discount,
        discountTimeout = 60,
        bookingUrl = "https://www.myawesomebookingweb.com",
    });

    const isBookingConfirmed = yield context.df.waitForExternalEvent("bookingConfirmed");

    context.df.setCustomStatus(isBookingConfirmed
        ? { message: "Thank you for confirming your booking." }
        : { message: "The booking was not confirmed on time. Please try again." }
    );

    return isBookingConfirmed;
});

import azure.functions as func
import azure.durable_functions as df

def orchestrator_function(context: df.DurableOrchestrationContext):
    userId = int(context.get_input())

    discount = yield context.call_activity('CalculateDiscount', userId)

    status = { 'discount' : discount,
        'discountTimeout' : 60,
        'bookingUrl' : "https://www.myawesomebookingweb.com",
    }
    context.set_custom_status(status)

    is_booking_confirmed = yield context.wait_for_external_event('BookingConfirmed')
    context.set_custom_status({'message': 'Thank you for confirming your booking.'} if is_booking_confirmed 
        else {'message': 'The booking was not confirmed on time. Please try again.'})
    return is_booking_confirmed

main = df.Orchestrator.create(orchestrator_function)

param($Context)

$userId = $Context.Input -as [int]

$discount = Invoke-DurableActivity -FunctionName 'CalculateDiscount' -Input $userId

$status = @{
            discount = $discount;
            discountTimeout = 60;
            bookingUrl = "https://www.myawesomebookingweb.com"
            }

Set-DurableCustomStatus -CustomStatus $status

$isBookingConfirmed = Invoke-DurableActivity -FunctionName 'BookingConfirmed'

if ($isBookingConfirmed) {
    Set-DurableCustomStatus -CustomStatus @{message = 'Thank you for confirming your booking.'}
} else {
    Set-DurableCustomStatus -CustomStatus @{message = 'The booking was not confirmed on time. Please try again.'}
}

return $isBookingConfirmed

@FunctionName("ReserveTicket")
public String reserveTicket(
    @DurableOrchestrationTrigger(name = "runtimeState") String runtimeState) {
        return OrchestrationRunner.loadAndRun(runtimeState, ctx -> {
            String userID = ctx.getInput(String.class);
            int discount = ctx.callActivity("CalculateDiscount", userID, int.class).await();
            ctx.setCustomStatus(new DiscountInfo(discount, 60, "https://www.myawesomebookingweb.com"));

            boolean isConfirmed = ctx.waitForExternalEvent("BookingConfirmed", boolean.class).await();
            if (isConfirmed) {
                ctx.setCustomStatus("Thank you for confirming your booking.");
            } else {
                ctx.setCustomStatus("There was a problem confirming your booking. Please try again.");
            }

            return isConfirmed;
        });
}

class DiscountInfo {
    public DiscountInfo() { }
    public DiscountInfo(int discount, int discountTimeout, String bookingUrl) {
        this.discount = discount;
        this.discountTimeout = discountTimeout;
        this.bookingUrl = bookingUrl;
    }
    public int discount;
    public int discountTimeout;
    public String bookingUrl;
}

Querying custom status with HTTP

The following example shows how custom status values can be queried using the built-in HTTP APIs.

public static async Task SetStatusTest([OrchestrationTrigger] IDurableOrchestrationContext context)
{
    // ...do work...

    // update the status of the orchestration with some arbitrary data
    var customStatus = new { nextActions = new [] {"A", "B", "C"}, foo = 2, };
    context.SetCustomStatus(customStatus);

    // ...do more work...
}

const df = require("durable-functions");

module.exports = df.orchestrator(function*(context) {
    // ...do work...

    // update the status of the orchestration with some arbitrary data
    const customStatus = { nextActions: [ "A", "B", "C" ], foo: 2, };
    context.df.setCustomStatus(customStatus);

    // ...do more work...
});

import azure.functions as func
import azure.durable_functions as df

def orchestrator_function(context: df.DurableOrchestrationContext):
    # ...do work...

    custom_status = {'nextActions': ['A','B','C'], 'foo':2}
    context.set_custom_status(custom_status)

    # ...do more work...

main = df.Orchestrator.create(orchestrator_function)

param($Context)

# ...do work...

Set-DurableCustomStatus -CustomStatus @{ nextActions = @('A', 'B', 'C'); 
                                         foo = 2 
                                        }  

# ...do more work...

@FunctionName("MyCustomStatusOrchestrator")
public String myCustomStatusOrchestrator(
    @DurableOrchestrationTrigger(name = "runtimeState") String runtimeState) {
        return OrchestrationRunner.loadAndRun(runtimeState, ctx -> {
            // ... do work ...

            // update the status of the orchestration with some arbitrary data
            CustomStatusPayload payload = new CustomStatusPayload();
            payload.nextActions = new String[] { "A", "B", "C" };
            payload.foo = 2;
            ctx.setCustomStatus(payload);

            // ... do more work ...
        });
}

class CustomStatusPayload {
    public String[] nextActions;
    public int foo;
}

While the orchestration is running, external clients can fetch this custom status:

GET /runtime/webhooks/durabletask/instances/instance123

Clients will get the following response:

{
  "runtimeStatus": "Running",
  "input": null,
  "customStatus": { "nextActions": ["A", "B", "C"], "foo": 2 },
  "output": null,
  "createdTime": "2019-10-06T18:30:24Z",
  "lastUpdatedTime": "2019-10-06T19:40:30Z"
}

Warning

The custom status payload is limited to 16 KB of UTF-16 JSON text. We recommend you use external storage if you need a larger payload.

Next steps

Learn about durable timers

Custom orchestration status in Durable Functions (Azure Functions)

Sample use cases

Visualize progress

Output customization

Instruction specification

Querying custom status with HTTP

Next steps

Additional resources